Apologies for the long list, been playing a lot in Ye Olden Days.
[My criteria of addictive games: "Ah, one more game / one more turn / one more...
Encounter (C64), when the special sound came up and you had to react really fast or die.
Forbidden Forest (C64), chilly atmosphere.
Civilization Series and
Monty Mole on the Run (C64)
I'd like to join ToG. Several friends are already members.
Guild Wars 2 (Desolation)